Also in Java: Switching or if-else chains on an `enum`. It's still a good practice to include a final `else` or `default` case, but it should really never happen. Actually, inclusion of the `default` case will be enforced by the compiler if it can detect a code path that doesn't return. [0]
enum Whatever { FOO, BAR }
if (whatever == FOO) {
} else if (whatever == BAR) {
} else {
// Should never happen!
}